Simplify the following expression: $r = \dfrac{-6k - 9}{6k - 3} \div 8$
Solution: Dividing by a number is the same as multiplying by its inverse. $r = \dfrac{-6k - 9}{6k - 3} \times \dfrac{1}{8}$ When multiplying fractions, we multiply the numerators and the denominators. $r = \dfrac{(-6k - 9) \times 1} {(6k - 3) \times 8}$ $r = \dfrac{-6k - 9}{48k - 24}$ Simplify: $r = \dfrac{-2k - 3}{16k - 8}$